The DGAT1 gene encodes for the diacylglycerol acyltransferase enzyme which catalyzes the final step in triacylglycerol synthesis. Various polymorphisms have been reported for DGAT1. One of them, the K232A DGAT1 polymorphism in which lysine as the 232nd amino acid is replaces by alanine, is associated with increased milk yield, lower fat and protein concentrations (Grisart et al., 2001) and altered milk fatty acid (FA) composition (Schennink et al.,2007). Milk FA composition is, on the other hand, also affected by nutritional factors including dietary FA composition (Sterk et al., 2011). Until now, no literature data could be retrieved to establish whether the response in milk FA composition of dairy cows to changes in dietary FA composition is influenced by DGAT1 polymorphism. Therefore, a study was performed with 8 rumen-cannulated dairy cows in mid-lactation with different DGAT1 polymorphism, receiving either palm fat or linseed oil.